Preheat the oven to 180ºC (160ºC fan) mark 4. Lightly oil a 33x20.5cm (13x8in) Swiss roll tin, then line it with non-stick baking parchment.
Step 2
Put the egg yolks into a large bowl. Add the sugar and vanilla extract, then whisk until light and pale. Sift in the cocoa, then fold in with a large metal spoon.
Step 3
In a spotlessly clean, grease-free bowl, whisk the egg whites until they form stiff peaks, then fold into the cocoa mixture. Spoon into the prepared tin, spread evenly and bake for 20-25min until just cooked - the top should be springy to the touch.
Step 4
Remove the roulade from the oven and leave to cool in the tin for 10-15min. Put a sheet of baking parchment on to the worksurface and dust with caster sugar. Carefully turn out the roulade on to the parchment, then leave to cool. When it's almost cold, carefully peel away the baking parchment away from the sponge.
Step 5
Meanwhile, make the filling. Put the chocolate into a large bowl and melt over a pan of barely simmering water, making sure the base of the bowl doesn't touch the water.
Step 6
In a separate bowl, lightly whip the cream with an electric hand whisk, then set aside. Take the bowl of melted chocolate off the heat, then use the electric whisk - there's no need to wash it - to beat the chestnut purée into the chocolate until smooth; the mixture will be quite thick. Whisk in the crème fraîche and icing sugar. Beat 1tbsp of the whipped cream into the chocolate mixture to loosen it, then use a metal spoon to fold in half the remainder.
Step 7
Spread the filling over the roulade, then spread the remaining cream over the top. Roll up the roulade, using the baking parch-ment to help you.
Step 8
Carefully lift roulade on to a serving plate and dust with caster sugar.
To freeze
Complete the recipe up to the end of step 7. Wrap the roulade in clingfilm and freeze for up to one month.
An experienced and highly skilled team of food writers, stylists and digital content producers, the Good Housekeeping Cookery Team is a close-knit squad of food obsessives. Cookery Editor Emma Franklin is our resident chilli obsessive and barbecue expert, who spends an inordinate amount of time on holidays poking round the local supermarkets seeking out new and exciting foods. Senior Cookery Writer Alice Shields is a former pastry chef and baking fanatic who loves making bread and would have peanut butter with everything if she could. Her favourite carb is pasta, and our vibrant green spaghetti is her weeknight go-to. Lover of all things savoury, Senior Cookery Writer Grace Evans can be found eating crispy corn and nocellara olives at every opportunity, and will take the cheeseboard over dessert any time (though she cannot resist a slice of tres leches cake). With a wealth of professional kitchen know-how, culinary training and years of experience between them, they are all dedicated to ensuring every Good Housekeeping recipe is the best it can be, so you can trust they’ll work (and if they don’t – we’ll have the answer for why*) every time (*90% of the time the answer is: “buy an separate oven thermometer”!).
